Unless the operating system has native tape driver support already built into
the kernel, you'll need to add an appropriate entry to a configuration file.
Otherwise, the device driver for the tape drive will revert to generic
settings which can impede performance dramatically. The correct file depends
on the operating system:
/kernel/drv/st.conf - solaris 2.x
/usr/kvm/sys/scsi/targets/st_conf.c - sunos 4.1.3_U1B
I know for certain that there is support for the exabyte 8505 and 8500 tape
drives in solaris 2.3 and solaris 2.4. However, there is no support for the
exabyte 8500c in solaris 2.3. In order to teach the scsi driver to recognize
it appropriately, I had to contact exabyte corporation and add the following
lines to the /kernel/drv/st.conf file and reboot the machine:
# Entry for the Exabyte EXB-8500C 8mm tape drive #
tape-config-list =
"EXABYTE EXB8500C", "Exabyte 8MM EXB8500C", "EXBT-8CC";
EXBT-8CC = 1,0x35,1024,0x0239,4,0x14,0x15,0x90,0x8c,3;
You might need to do the same for the DLT 2000. I hope this helps.
-Steven McElwee
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-- original message follows --
> From: Steve Mattson <[EMAIL PROTECTED]>
> To: [EMAIL PROTECTED]
> Subject: DLT drive performance on SunOS 4.1.3 afs backups?
> Date: Fri, 18 Aug 1995 11:04:00 +0100
> Hi,
>
> Some people here have been evaluating a DLT 2000 drive for doing standard
> unix dumps. As compared to an Exabyte 8505 they're getting quite a
> performance increase. They can achieve ~60 MB per minute sustained
> transfer rates to the drive. The drive is rated at a max of 1.25 MB/sec
> and so a 1 MB/sec transfer rate like this seems appropriate. They had
> gotten some lower rates at first and then found that by bumping up the
> block size option to dump they could achieve the above rates.
>
> On the same machine, using the same two drives, I can't get anywhere
> near that performance using afs backup/butc. I'm seeing around 10 MB
> per minute on both the DLT 2000 and on the Exabyte 8505. I can't see
> any option that would let me bump up the block size in a similar manner,
> if indeed that's what I need to be able to do to get better sustained rates.
> I *can* hear the drive starting and stopping all the time when the afs
> backup is running, so I know it's not streaming like it should be.
>
Does anyone have
> any good experiences getting these drives to perform at rated speeds
> and wisdom that they could pass along? The machine in question and
> the servers I'm dumping from are on an fddi ring and given that the
> unix dumps can get higher rates than I'm seeing it doesn't seem to be
> strictly a hardware issue.
>
> Thanks,
>
> Steve Mattson
> University of Michigan - CAEN
